Effect of Bromocriptine Administration on Maintenance of Late Pregnancy in the Pig

Summary

Plasma concentrations of prolactin, luteinizing hormone (LH) and progesterone were determined in pregnant gilts (n = 6) administered bromocriptine from 67 — 72 days of pregnancy. Blood samples were taken daily at 2 h intervals from 60 to 80 days of pregnancy. Bromocriptine treatment reduced prolactin from 9.7 ± 1.4 before to 1.9 ± 0.6 ng/ml during the treatment (p ≤ 0.05) and then returned to the pre-treatment concentrations (10.5 ± 2.0) following cessation of bromocriptine.

Bromocriptine increased LH from 1.4 ± 0.2 before treatment to 2.9 + 0.5 ng/ml (p ≤ 0.01) during administration and maintained elevated (3.0 ± 0.7) in the post-treatment period (p ≤ 0.05). Administration of bromocriptine did not alter progesterone concentration in plasma (7.5 ± 1.2; 7.2 + 1.6 and 6.6 ± 1.6 ng/ml in pre treatment, treatment and post-treatment periods, respectively). This study shows that decrease of prolactin level by bromocriptine treatment does not cause depletion of progesterone secretion in late pregnant pigs.

Key words

Pig - Late Pregnancy - Bromocriptine - LH